1. Field of the Invention
The present invention relates to a fastening device, and more particularly to a fastening device including a cooling unit made of an elastic material with a high thermal conductivity, wherein the fastening device is used for a backlight module.
2. Description of Related Art
The development of the digital technology affects the work and the life of people living in the 21 century. One kind of digital technology instrument, i.e. liquid crystal display equipment, is popularly applied to the daily life. The liquid-crystal panels of the liquid crystal display industry can be applied to notebook computers, liquid-crystal monitors, portable consumable image products, music products, cell phones and liquid-crystal televisions.
A backlight module of an LCD device is a common structure for providing the uniform light. The backlight module has many advantages of, e.g. a stable emitting efficiency and a long operational life. However, most of the light sources of the backlight modules are made of glass and produce a lot of heat while the light source is operated. The operated light source has to be cooled for maintaining the stability of the emitting efficiency and the operational life.
Referring to FIG. 1A, which illustrates a vertical view of a conventional bottom-lighting LCD device 10. A light source 101 and other optical elements (not shown) such as a diffusing plate, a reflecting plate, and a polarizing plate are assembled within the case 111 of the LCD device 10. And the edge of the light source 101 is clipped by an upper frame 103 (or is called “front frame”) and a lower frame 105 (or is called “back frame”) to ensure that the light will emit along a designed direction, such as the direction indicated by the arrows in FIG. 1A. Besides, in order to cool the heat produced by the light source 101, a cavity 107 are formed to allow the air circulating through the cavity 107.
However, cooling the light source 101 by providing the cavity 107 between the upper frame 103, the lower frame 105 and the light source 101 is not effectively. Furthermore, the quality of the LCD device is affected because the dust may drop in the cavity 107 and interfere the light emitting from the light source 101.
Another conventional LCD device is shown in FIG. 1B. Elastic element such as resin (not shown) or a slice of rubber 109 is provided and stuffed between the frame 103 and the light source 101 to ensure that the light will emit along a designed direction, such as the direction indicated by the arrows in FIG. 1B and to absorb the oscillation arising from external force.
However, the rubber 109 does not have a high thermal conductivity. The quality and the operational life of the light source 101 is decreased because there is not enough space for cooling.
Thus it is necessary to develop a fastening device to overcome the disadvantage of the prior art for radiating the heat from the light source more effectively, and preventing the oscillation that affects the operating stability of the light source, the quality of the light, and the operational life of the light source.